274
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
Agafonov et al.
Scheme 1
R = Prn (2, 6a—c, 8a—c); Bun (3, 7a—c, 9a—c)
1, 6—9: the substituents are in orthoꢀ (a), metaꢀ (b),
and paraꢀpositions (c)
extract as picrates by adding a solution of picric acid (2.5 mmol)
in 2 mL of EtOH. The picrates were filtered off, washed with
2 mL of EtOH, dried, and eluted with CHCl3 through an Al2O3
layer (h = 1 cm) to separate off the picric acid. The eluates were
concentrated to give analytically pure amines as oils or lowꢀ
melting solids.
6a. 1H NMR, δ: 1.00 (t, 3 H, Me, J = 7 Hz); 1.45—1.65 (m,
2 H, CH2); 2.70—2.90 (m, 2 H, NCH2); 2.90—3.30 (3 H, NH2,
NH); 6.40—6.90 (m, 4 H, H arom.).
6c. 1H NMR, δ: 1.00 (t, 3 H, Me, J = 7 Hz); 1.40—1.60 (m,
2 H, CH2); 2.60—2.80 (m, 2 H, NCH2); 2.90—3.60 (3 H, NH2,
NH); 6.65—6.75 (m, 4 H, H arom.).
7a. 1H NMR, δ: 0.95 (t, 3 H, Me, J = 7 Hz); 1.20—1.60 (m,
4 H, (CH2)2); 2.60—2.80 (m, 2 H, NCH2); 2.90—3.60 (3 H,
NH2, NH); 6.50—7.00 (m, 4 H, H arom.).
larities. Compounds 1a,c in dioxane (ε = 2.21) and MeCN
(ε = 36.2) yield only dialkyl derivatives, whereas their
reactions in CH2Cl2, with an intermediate dielectric conꢀ
stant (ε = 8.9), afford monoalkyl derivatives only, which
clearly indicates the activating effects of dioxane and
MeCN on the process. The polar properties of the latter
solvents seem not to be so important here. Apparently,
this effect is due to their crystallization under a pressure of
10 kbar, while CH2Cl2 remains liquid and does not actiꢀ
vate the process further.
Acceleration of other reactions under high pressures
due to solvent crystallization and possible reasons for this
phenomenon have been described earlier (see Ref. 9 and
references cited therein).
7c. 1H NMR, δ: 1.00 (t, 3 H, Me, J = 8 Hz); 1.20—1.50 (m,
4 H, (CH2)2); 2.70—2.90 (m, 2 H, NCH2); 3.00—3.50 (3 H,
NH2, NH); 6.65—6.75 (m, 4 H, H arom.).
Experimental
8a. Found (%): C, 74.60; H, 10.72; N, 14.45. C12H20N2.
Calculated (%): C, 74.95; H, 10.48; N, 14.57. 1H NMR, δ: 1.00
(t, 6 H, 2 Me, J = 7 Hz); 1.30—1.70 (m, 4 H, 2 CH2); 2.70—2.90
(m, 4 H, 2 NCH2); 2.90—3.50 (2 H, 2 NH); 6.40—6.80 (m, 4 H,
H arom.).
8b. Found (%): C, 75.41; H, 10.47; N, 14.91. C12H20N2.
Calculated (%): C, 74.95; H, 10.48; N, 14.57. 1H NMR, δ: 0.95
(t, 6 H, 2 Me, J = 7 Hz); 1.30—1.50 (m, 4 H, 2 CH2); 2.70—2.90
(m, 4 H, 2 NCH2); 2.90—3.30 (2 H, 2 NH); 6.00—6.20 (m, 3 H,
H arom.); 6.85—6.95 (m, 1 H, H arom.).
8c. Found (%): C, 74.58; H, 10.90; N, 14.89. C12H20N2.
Calculated (%): C, 74.95; H, 10.48; N, 14.57. 1H NMR, δ: 1.00
(t, 6 H, 2 Me, J = 7 Hz); 1.35—1.65 (m, 4 H, 2 CH2); 2.60—2.80
(m, 4 H, 2 NCH2); 3.00—3.60 (2 H, 2 NH); 6.70 (s, 4 H,
H arom.).
9a. Found (%): C, 76.71; H, 11.35; N, 12.44. C14H24N2.
Calculated (%): C, 76.31; H, 10.98; N, 12.71. 1H NMR, δ: 1.00
(t, 6 H, 2 Me, J = 8 Hz); 1.30—1.70 (m, 8 H, 2 (CH2)2);
2.60—2.80 (m, 4 H, 2 NCH2); 2.80—3.70 (2 H, 2 NH);
6.50—6.90 (m, 4 H, H arom.).
Melting points were determined on a Boetius hot stage.
1H NMR spectra were recorded on a Bruker ACꢀ200 instrument
in CDCl3. GLC and MS analyses were carried out on a Finnigan
MAT INCOSꢀ50 instrument (EI, 70 eV, capillary column
30 m × 0.25 mm with polydimethylsiloxane (0.25 µm) as a
grafted phase). Bis(azomethines) 1a—c were prepared accordꢀ
ing to the known procedures.10—12
Alkylation of bis(azomethines) 1a—c under high pressure (genꢀ
eral procedure). A solution of a bis(azomethine) (1a—c) (1 mmol)
and an alkyl chloride (2 or 3) (2.2 mmol) in 1 mL of CH2Cl2,
dioxane, or MeCN in a Teflon tube was kept at 50 °C and a
pressure of 10 kbar for 5 h. The reaction mixture was cooled,
concentrated in vacuo, acidified with 20% HCl (3 mL), and
refluxed for 10 min. After cooling, benzaldehyde was extracted
with Et2O (2×5 mL). The aqueous layer was alkalified with a
solution of NaOH to strongly alkaline reaction, the alkylated
phenylenediamine was extracted with Et2O (3×5 mL), and the
extract was analyzed by GLC.5 Analytically pure amines were
obtained by precipitation of compounds 6—9 from the ethereal